P308
Formation Process of Si Nanoparticles Resulting from Laser Ablation Observed by a Decomposition Method
T. Makimura(*), T. Mizuta(*), T. Ueda(*), D. B. Geohegan(**), D. H. Lowndes(**), K. Murakami(*)
(*)Institute of Materials Science, University of Tsukuba, (**)Solid State Division, Oak Ridge National Laboratory

Light-emitting Si nanoparticles with size of 1-10 nm can be fabricated by cooling of Si atoms that are ejected from Si targets in rare gas by laser ablation. Utilizing this pulsed and clean technique, we may fabricate nanoparticles with well-defined structures. For this purpose, it is important to understand the dynamics of the formation process of the nanoparticles. For measuring time-resolved spatial distribution of the particles, we have developed a technique. It utilize light emission resulting from decomposition of the nanoparticles by irradiation of second laser light. This method is sensitive from molecules that consist of several atoms to particles with size of more than 10 nm. Applying the technique, we directly observed a) that particles begin to be formed 300 micro sec after the ablation in 2-Torr Ar gas and b) that they grow until 1 msec.
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